Question

I want to validate a textbox which rounds to two decimal places. However, I do not want to round up.

For example; if I enter 19.999 then the result will be 19.99, not 20.00

And if I enter 19.7, then result will be 19.70. If I enter 19, then result will be 19.00

The toFixed() function is not working in my code.

Can someone please help me with this?

Answer 1

function withPrec(number, digitsAfterComma) {
    if (digitsAfterComma <= 0 || digitsAfterComma > 10) return number; // bad args
    var str = String(number);
    var comma = str.indexOf('.');
    var zeroes = '0000000000'.substring(0, digitsAfterComma);
    return (comma == -1) ? 
        str + '.' + zeroes : (str + zeroes).substring(0, comma + digitsAfterComma + 1);
}    

Using substring to avoid building an intermediate array.

Use as withPrec(10.00001, 2) or withPrec(1, 5);